Anastasia K. Fragkou, Christopher Old, Vengatesan Venugopal, Athanasios Angeloudis

Wave-current interaction phenomena are often represented through coupled model frameworks in ocean modelling. However, the benchmarking of these models is scarce, revealing a substantial research challenge. We seek to address this through a selection of benchmark cases for coupled wave-current interaction modelling frameworks. This comprises a series of analytical and experimental test cases spanning three diverse conditions of wave run-up, one scenario of waves opposing a current flow, and a 2-D arrangement of waves propagating over a submerged bar. We simulate these through coupling of the spectral wave model, Simulating WAves Nearshore (SWAN), with the coastal hydrodynamics shallow-water equation model, Thetis, through the Basic Model Interface (BMI) structure. In our analysis, by comparing calibrated versus default parameter settings we identify and highlight calibration uncertainties that emerge across a range of potential applications. Calibrated model results exhibit good correlation against experimental and analytical data, alongside benchmarked wave-current model predictions, where available. Specifically, inter-model comparisons showcase equivalent accuracy. Finally, the coupled model we developed as part of this work showcases its ability to account for wave-current effects, in a manner extensible to other coupled processes through BMI and applicable to more complex geometries.